1. Field of the Invention
The present invention relates to a memory card casing, and more particularly to memory card casing having ridges and ribs formed on a bottom cover of the casing so as to provide sufficient force to support thereon contacts of a printed circuit board.
2. Description of Related Art
Digital cameras and other electronic devices such as cell phones depend on memory cards to store valuable information. According to their information storing capabilities, memory cards for storing large quantity of information may be divided into an SD (secure digital) card and an XD (extreme digital) card. However, because the thickness of the printed circuit board (PCB) of the memory card is reduced to less than 0.3 mm and respective thickness for the top cover and the bottom cover of the casing for receiving therein the PCB is less than 0.2 mm, the rigidness of the memory card is not sufficient. That is, the memory card is easily distorted and damaged especially when inserted into the receiving port of an electronic device. Moreover, the PCB normally has multiple contacts extending out of the casing for engagement with legs extending from the receiving port of the electronic device. Under the situation that there is no sufficient support to the contacts, the contacts are easily damaged when engaging with the legs of the electronic device.
With reference to FIG. 1, a conventional memory card casing is shown and composed of a top casing (1) and a bottom casing (2). The top casing (1) has multiple openings (11) defined in a peripheral edge of the top casing (1) for exposing contacts on a PCB. In order to support and sandwich the PCB with the top casing (1), the bottom cover (2) has multiple columns (21) and ears (22) formed on a peripheral edge of the bottom cover (2) to correspond to a space between two adjacent openings (11) such that the columns (21) and the ears (22) are able to support the contacts of the PCB after the PCB is sandwiched between the combination of the top cover (1) and the bottom cover (2). Because the support from the columns (21) and ears (22) can only provide little support rigidness to the PCB contacts, the contacts are still easily damaged and distorted when inserted into the receiving port of an electronic device.
To overcome the shortcomings, the present invention tends to provide an improved memory card casing to mitigate the aforementioned problems.